31 mm wrench for cord grips?

Factual Questions
1

What’s the right tool for tightening the 31 mm drive nuts on 3/4" cord grips?

The cord grip, or strain relief, is a fitting that lets a cable pass through the sheet metal wall of an electrical enclosure. It has a slender nut whose flats are just a tad under 31 mm apart, and also body flats and flats on its gland nut, also 31 mm. These are aluminum, or nickel plated brass, or zinc, and they typically rest against exposed painted surfaces, often crowded near obstacles. Tightening them with big pliers or adjustable wrenches can be hard to do, especially if you don’t want to slip off or otherwise scratch and gouge things.

But I can’t find a 31 mm wrench for sale. A 32 mm wrench or a 1 1/4" wrench is very loose and threatens to pop over the soft, chamfered corners of the nut, and a 30 mm wrench or 1 3/16" wrench won’t fit.

Where can you buy a 31 mm wrench, say a combination wrench and a socket wrench or even the open box style flare nut wrench? If not, then, what tool do you use to do this without making a mess?

2

Go to Harbor Freight, buy a 30mm wrench, and then grind it to the right dimension.

3

I know it’s basic, but google has many hits for 31mm combo wrenches.

4

Are you talking about these? Usually I either tighten with a flat head screwdriver-push on one of the flanges of the nut- or hand tighten the nut then turn the outer portion.

5

Khendrask, I’ll be damned. I tried “31 mm wrench” and a variety of other searches but didn’t turn up your link. None of the couple dozen links I followed actually offered the 31 mm size, including McMaster-Carr and MSC Direct. Yet, there it is, big as life! Thanks! I ordered 3. At less than $9, they would make great stocking-stuffers…

Paintcharge, you link to the kinds of nuts with what look like gear teeth on the outside (I don’t know the correct term for that). I’m using some special EMI-proof ones and some aluminum ones, which have a hex outside instead. But, in any case, how do you turn (or hold) the outer portion? If it’s with pliers or a big adjustable, don’t they tend to slip and mar things? With a stamped steel conduit box inside a wall, it wouldn’t matter, but how would you do it with shiny plated cord grips on a painted control panel?

6

you want strain relief clamps to dig into the paint both for locking force and grounding. the nut will have teeth or a beveled face for that purpose.

7

If you mean seal tight, with the hexagon edges, we just use channel locks.
If you mean those other ones, with the pointy things on em, we use a screwdriver and linesman pliers to pound with. :smiley:

8

That is the way I do it.
Does everyone know the proper name of an electritions linesman pliers??

Why it is a hammer.

9

I should probably pick up a set of those fancy hammers, I have a bad habit of using the bottom of my cordless drill.

10

Every tool is a hammer. Except for chisels, those are screwdrivers.

11

And hammers. Those are shims, and pry bars, and weights, and fine adjusters.

12

:DLOL:p